System for and Method of Network Booting of an Operating System to a Client Computer Using Hibernation

1. A method for booting a client computer to a predetermined state via a network, the method comprising: issuing, by a client executing emulation code and client disk access interrupt procedures, a request for a first set of sectors of a virtual hard disk associated with a server computing device, the first set of sectors comprising a first boot file; receiving, via the network, the first boot file from the server computing device; executing the contents of the first boot file, the executing comprising: installing a second client disk access interrupt handler procedure that intercepts a read request and a write request to a hard disk, forwards the read request to the server computing device, and caches the write request to prevent the write request from being executed at the virtual hard disk to preserve the state of the virtual hard disk; and issuing a second request for a second set of sectors that comprise a second boot file; receiving, from the server computing device, the second boot file, the second boot file comprising an O/S boot file; executing the second boot file, the executing comprising: issuing a third request for a third set of sectors comprising a hibernation image; receiving the hibernation image, the hibernation image comprising the contents of local memory, memory management information, and other state information needed to restore the client to the pre-determined operating state; loading the hibernation image into client memory; and initializing drivers, data structures and applications associated with the O/S to thereby restore the client computer to the predetermined state.

2. The method of claim 1 wherein the second client disk access interrupt handler caches the write requests locally at the client.

3. The method of claim 1 wherein the second client disk access interrupt handler caches the write requests at a location on the network.

4. The method of claim 1 wherein the emulation code comprises PXE code resident on the client.

5. The method of claim 1 wherein initializing drivers comprises initializing a network filter driver and a storage driver to enable server emulation.

6. The method of claim 1 wherein receiving the hibernation image comprises receiving the hibernation image via the server.

7. The method of claim 1 wherein receiving the second boot file comprises, receiving the second boot file on a sector-by-sector basis.

8. The method of claim 7 further comprising requesting, by the client, retransmission of one of the sectors of the second boot file.

9. The method of claim 1 wherein receiving the hibernation image comprises, receiving the hibernation image on a sector-by-sector basis.

10. The method of claim 9 further comprising requesting, by the client, retransmission of one of the sectors of the hibernation image.

11. A computer readable medium having instructions thereon that when executed cause a client computer to boot to a predetermined state via a network, the computer readable medium comprising: instructions to issue, by a client executing emulation code and client disk access interrupt procedures, a request for a first set of sectors of a virtual hard disk associated with a server computing device, the first set of sectors comprising a first boot file; instructions to receive, via the network, the first boot file from the server computing device; instructions to execute the contents of the first boot file, the instructions to execute comprising: instructions to install a second client disk access interrupt handler procedure that intercepts a read request and a write request to a hard disk, forwards the read request to the server computing device, and caches the write request to prevent the write request from being executed at the virtual hard disk to preserve the state of the virtual hard disk; and instructions to issue a second request for a second set of sectors that comprise a second boot file; instructions to receive, from the server computing device, the second boot file, the second boot file comprising an O/S boot file; instructions to execute the second boot file, the instructions to execute comprising: instructions to issue a third request for a third set of sectors comprising a hibernation image; instructions to receive the hibernation image, the hibernation image comprising the contents of local memory, memory management information, and other state information needed to restore the client to the pre-determined operating state; instructions to load the hibernation image into client memory; and instructions to initialize drivers, data structures and applications associated with the O/S to thereby restore the client computer to the predetermined state.

12. The computer readable medium of claim 11 wherein the second client disk access interrupt handler caches the write requests locally at the client.

13. The computer readable medium of claim 11 wherein the second client disk access interrupt handler caches the write requests at a location on the network.

14. The computer readable medium of claim 11 wherein the emulation code comprises PXE code resident on the client.

15. The computer readable medium of claim 11 wherein the instructions to initialize drivers comprise instructions to initialize a network filter driver and a storage driver to enable server emulation.

16. The computer readable medium of claim 11 wherein the instructions to receive the hibernation image comprise instructions to receive the hibernation image via the server.

17. The computer readable medium of claim 11 wherein the instructions to receive the second boot file comprise instructions to receive the second boot file on a sector-by-sector basis.

18. The computer readable medium of claim 17 further comprising instructions to request, by the client, retransmission of one of the sectors of the second boot file.

19. The computer readable medium of claim 11 wherein the instructions to receive the hibernation image comprise instructions to receive the hibernation image on a sector-by-sector basis.

20. The computer readable medium of claim 19 further comprising instructions to request, by the client, retransmission of one of the sectors of the hibernation image.

21. A system for booting a client computer to a predetermined state via a network, the system comprising: means for issuing, by a client executing emulation code and client disk access interrupt procedures, a request for a first set of sectors of a virtual hard disk associated with a server computing device, the first set of sectors comprising a first boot file; means for receiving, via the network, the first boot file from the server computing device; means for executing the contents of the first boot file, the means for executing comprising: means for installing a second client disk access interrupt handler procedure that intercepts a read request and a write request to a hard disk, forwards the read request to the server computing device, and caches the write request to prevent the write request from being executed at the virtual hard disk to preserve the state of the virtual hard disk; and means for issuing a second request for a second set of sectors that comprise a second boot file; means for receiving, from the server computing device, the second boot file, the second boot file comprising an O/S boot file; means for executing the second boot file, the means for executing comprising: means for issuing a third request for a third set of sectors comprising a hibernation image; means for receiving the hibernation image, the hibernation image comprising the contents of local memory, memory management information, and other state information needed to restore the client to the pre-determined operating state; means for loading the hibernation image into client memory; and means for initializing drivers, data structures and applications associated with the O/S to thereby restore the client computer to the predetermined state.

22. The system of claim 21 wherein the second client disk access interrupt handler caches the write requests locally at the client.

23. The system of claim 21 wherein the second client disk access interrupt handler caches the write requests at a location on the network.

24. The system of claim 21 wherein the emulation code comprises PXE code resident on the client.

25. The system of claim 21 wherein the means for initializing drivers comprises means for initializing a network filter driver and a storage driver to enable server emulation.

26. The system of claim 21 wherein the means for receiving the hibernation image comprises means for receiving the hibernation image via the server.

27. The system of claim 21 wherein the means for receiving the second boot file comprises the means for receiving the second boot file on a sector-by-sector basis.

28. The system of claim 27 further comprising means for requesting, by the client, retransmission of one of the sectors of the second boot file.

29. The system of claim 21 wherein the means for receiving the hibernation image comprises means for receiving the hibernation image on a sector-by-sector basis.

30. The system of claim 29 further comprising means for requesting, by the client, retransmission of one of the sectors of the hibernation image.